They do sell diapers, but they are VERY expensive and in limited quanities both in what is sold and what is stocked. So, it is possible if ths is your only source of diapers they might run out by the end of the cruise. Remember this is a ship that only loads supplies usually on embarkation day, so it is possible they might run out of things to sell if they don't suply enough for demand. Look what happened on the Repo cruise with some of the special items, pins, t-shirts, ect. I'd bring your own, and figure the extra space available on the way back as room for souveniers.